Customers and Patrons of the Mad-Trade: The Management of Lunacy in Eighteenth-Century London by Jonathan Andrews and Andrew Scull 209pp, California, £29.95

Through my door today came a small, green card: "Sheik Imam, Godgifted Marabout, he work with very powerful spirits can help for all your problems regarding love, lucky, work, exams, business, black sickness, protection against evils spirits, future regarding sexual impotency etc." At the bottom of the card was a local phone number and address. It immediately struck me how like the problems seen by a community psychiatrist these were. Yet the language used on this card was reminiscent rather of the world of John Monro's fascinating casebook of 1766.

Monro's casebook is published here by Andrews and Scull as part of their exploration of what they term the "mad-doctoring" trade in the 18th century. Monro was the second of a dynasty of medical practitioners who ran the Bethlem Hospital from 1728-1853. His work there spread over four decades, until his death in 1791.

The Bethlem was a monastic foundation dating from 1247 and a centre for the care of the mentally ill since the early 15th century. In Monro's day, the Bethlem, or "Bedlam" as it became popularly known, was a place where people were confined if they were too poor to afford specialist care at home, or if they were unmanageable in the community. There they could be gawped at by the public from viewing galleries. Artists would draw the patients in such extreme poses as "rage" and "melancholy", as though witnessing at first hand the passions locked within all of us. Society gentlemen would spend the afternoon observing the "lunatics".

In spite of the eminence of Monro's position at the Bethlem, most of his time was spent on his more lucrative private patients. These are the people who feature in the casebook. Monro did not intend the book for publication and it was still in the possession of distant relatives of the Monro family when Andrews discovered it. The book records Monro's 100 cases of mental disorders during a single year. It reveals a world of consultations in patients' homes and of negotiations between patients and their families. Monro did not see only the aristocracy or rich merchant class. A large proportion of his patients came from the middle or lower layers of society. His patients ranged from peers of the realm to grocers, bakers' wives and city clergy.

His role seems to have been to decide whether a person was mentally ill or not, and if so whether or not they needed treatment. Monro is rather sophisticated and broad-minded in determining the possible causes of mental illness. Along with his strong sense that illnesses were somehow hereditary, he identified impoverishment, upset, bereavement, love, fright, shock, rejection and physical and verbal abuse as causes of mental disorder. However, he also refers to the "lunar cycle" as of significance in several of his cases.

Of the treatments themselves, the casebook reveals very little. Given the 18th-century medications described by Andrews and Scull, the least said the better. The best you could hope for was to be sent to the baths at Ramsgate, the worst to be given Robert James's famous Fever Powders, a mixture of mercury and antimony.

Like today's psychiatrists, Monro describes the appearance and speech of his patients, though he is rather less circumspect in his observations. Patients talk "loudly" or "incessantly", as in the cases of Mrs Edge and Mrs Holford, whom Monro describes as "full of talk" or liable to "ramble". Yet the vividness of his histories shows how absorbed he was in trying to comprehend his patients' distress. He describes a Mr Walker who "told me that the Devil left him this morning about four o'clock that he had been with him seven years, was brown and of a size between a mouse and a rat. He inform'd me that there were but two starrs left, the rest having fallen that he had seen them; . . . that about 27 years ago he saw the fall of mankind, in company with a very good man, who keeps the Sun Tavern in Westminster, that many years ago he kill'd a hare which he did not think to be a common hare but was something he knew not of what infinite power."

Monro also takes great interest in his patients' gait, their appearance and the examination of bodily excreta and secreta. He has no established practice of neurological examination to help him, nor has he computer scans to guide him. Much of his work deals with gross symptoms that would indicate to him a poor prognosis, such as apoplexy or convulsions.

In the 18th century, doctors who specialised in treating the mentally ill sought to enlarge their practice to include "nervous troubles" consisting of such disorders as hypochondria, hysteria, the spleen and the vapours. Monro's casebook vividly reflects the variety of mental health problems that he saw. He frequently includes follow-up statements at the end of his brief histories. Sometimes these are cryptic, but often the phrase "he died suddenly" creeps in in tiny handwriting as in the following account:

"Mr Alderman Peers has call'd on me often with complaints strongly hypochondriacal but is much afraid he shall lose his senses, he constantly wakes about four o'clock in the morning, is in violent hurries and in great horror, which does not go off till he gets up, then he is very well, he has a good appetite and uses proper exercise, and is regular and temperate - he died suddenly."

Then as now medicine could be a lesson in humility. Monro's case histories give us an unusual insight into the kinds of illnesses that would be presented to a doctor in 18th-century London. Although Monro can be harsh in his judgments, often dismissing patients' speech as "nonsense", he has his soft spots, notably for young women jilted in love.

Encasing Monro's book is Andrews and Scull's elegant discussion of the conditions that formed the backdrop for treatment of the mentally ill in the 18th century. Although there remains something of the Godgifted Marabout about it, 18th-century medicine as practised by Monro seems less removed from the dilemmas of modern psychiatry than it initially appears. His firsthand accounts of his patients' distress retain their freshness, and his interest in some of the great unsolved questions of psychiatry is undimmed.